I'm considering a UT-3000 control board in a three-zone, dual fuel system.

Assuming one of the zones has a Goodman CTK04, what would be the recommended choice of thermostat for the other two zones? I've seen the term 'slave thermostat' used in the forums, which seems to describe this use case. I would want them to work over ComfortNet (and therefore 'plug-and-play' with the UT-3000 board) and also be compatible with a RedLink internet gateway so that the whole system can be controlled remotely.

Apologies if this question has already been asked and answered but I was unable to search the forum for either 'ut-3000' or 'thermostat'

Not an answer to your question but rather a "thank you". I installed this forum and I never knew there was a search setting for excluding common words. If you only knew how many times I've visited forums with a simple trouble shooting question just to be told they couldn't help me because my words were too common.

Well I'm not about to let this forum be that aggravating. All I had to do was shut off the limit and recreate the index. Feel free to search away! Thanks for the heads up.

The UT3000 is compatible with the CTK01, CTK02, CTK03 and CTK04 (communicating) thermostats. The older models may not be available anymore.

The CTK04 is "Red Link" ready and accessible via your smart phone with the Honeywell Gateway.

The reason EWC highly recommends that each zone system have at least one (1) CTK04 is primarily for the benefit of the Installer/Technician and the Equipment itself:
* Initial system Start-up and Calibration tests are performed via the CTK04 thermostat.
* Accessing the Outdoor and Indoor unit "advanced menus", as well as the "Installer Options" menu, is facilitated thru the CTK04.
* Airflow adjustments and "tweaking" the system settings are also facilitated via any CTK04, connected to the UT3000.
* Any "fault/failure" conditions that occur in the equipment will be sent to the thermostats for the Technician or Homeowner to observe.
* In the case of the Inverter, servicing the sealed system requires a CTK04! For instance, you cannot "pump down" the unit without a CTK04. You can also "force a defrost" cycle with the CTK04.

Now, having said that...There are many Homeowners and Contractors who opt to avoid CTK04's altogether. The reasons vary from cost to simply wanting their own "preferred" type of thermostat. This is fine so long as the servicing technician carries a CTK04 on his/her truck, to use as a tool. The CTK04 is temporarily connected to the UT3000 (disconnect any existing zone thermostat) and allow the CTK04 to "find" the system. Initial system commissioning can then be performed. Fault conditions can be documented & then cleared. System adjustments (CFM/Ton) can be performed. The Technician then removes the CTK04 and re-connects the existing thermostat.

FYI...Heads up, the VisionPRO 8000 is not Climate Talk compatible.

If you have any questions or concerns, please call me to discuss. As you can tell, it is a lengthy subject.

As a follow-up to your post. Any (non-communicating) Honeywell Thermostat that is "Red Link" capable can be used as Zone 2 & 3. They would be picked up by the HW Gateway just like the CTK04 would.

You could create a "portfolio" of thermostats to monitor on your Smart Phone...But the non-communicating thermostats would not be able to access the HVAC system, like the CTK04 can. Matters not, because you only need one CTK04 to access the system. The others would be superfluous.

There are two reasons to install CTK04's throughout the home:
[*] Desire for symmetry throughout the home....All thermostats look the same and operate the same. I only have one thermostat to learn!
[*] The CTK04 puts out a "proportional" Heating, Cooling or Fan demand. It can ask for a "percentage" of the system's BTU capacity ( 30%, 50%. 75%, 100%, etc). As the zone temperature gets close to the set-point, it lowers that demand. A regular 24 volt thermostat cannot do that. Thus, the non-communicating thermostat demands are interpreted as 50% - 100%. The UT3000's PID loop was designed to work with Proportional inputs. Legacy inputs simply mean that the zone thermostat cannot lower it's demand as the zone gets "close" to satisfying.

John, thank you for the detailed response. It is very much appreciated.

I am definitely planning at least one CTK04 but I was hoping to keep costs down by using cheaper thermostats for zones 2 & 3.

Thanks for clarifying that the visionPRO 800 is not ClimateTalk compatible. However, I do see that the TH8110R1008 model of that thermostat uses Red Link. Does a Red Link connection provide the same functionality (in terms of proportional demand) as a wired connection using the Climate Talk protocol?

If there is an advantage to using a hard-wired Climate Talk compatible thermostat, are there any other options other than the CTK04? I have been unable to find anything online.

Red Link is not the same as Climate Talk. Red Link is Honeywell's "wireless" feature/function, that allows you to connect auxiliary devices such as Outside air sensors, Room sensors, Remote access Gateway, etc.

Climate Talk is the "wired" protocol/language that the HVAC system, the Zone Controller and the CTK04 are operating on. These devices, when connected together creates a "network" of components that are talking to each other, in order to heat & cool your house.

There are no other thermostats that operate under the Climate Talk language other than those I mentioned before. CTK01, CTK02, CTK04, CTK04.

You don't need 2 or 3 CTK04's....You only need one!....Use less expensive thermostats in other zones to save money.

If you want remote access to ALL of your thermostats (including the CTK04), buy other (less expensive) Honeywell thermostats that have Red Link capability. Buy the Gateway also, then synch the CTK04 and the other two HW thermostats to that Gateway and setup the account on the HW website.

thanks again for the reply. Final question: for a dual fuel setup with a modulating furnace and a two-stage heat pump (Goodman DSZC16) and the UT-3000 zone board, do the red link thermostats need to also be two-stage or can I get away with a pair of single stage models, such as the Honeywell TH8110R1008?

If I may ask a follow up, do you know if the Honeywell Prestige IAQ is the same thermostat as the CTK04? It looks like it is, but one important difference I see in the (limited) Honeywell documentation is they make it appear that the Prestige is wireless only. They don't show or make any reference to the two data lines, just a two line hookup for power.

If it is wireless only, and I want to connect five of them to two different UT-3000's on two separate HVAC systems (one 2 zone, one 3 zone), I'm trying to figure out how/if it will work. I have an installer that will install new HVAC equipment, the Prestige stats, and a Honeywell HZ322 zone controller (through a RedLink to TrueZone interface, THM4000R1000).

My thought is to replace the zone controller with the UT-3000 after, but I'm not sure how that will work if all the stats are wireless only.